Apparatus for applying adhesive to the edges of a slit tube

ABSTRACT

Foamed tubular insulation is provided with a slit down its longitudinal length so that it may be slid over a pipe. The apparatus herein opens up the tubing so that an adhesive coater may apply an adhesive to both edges of the slit in the tubing. A flattening structure opens up the tube so that the two surfaces to be coated are in the same horizontal plane, and a roll coating structure then applies adhesive to the edges in the same plane. The adhesive is permitted to dry and is then later solvent actuated when it is to be utilized to fasten the two edges together.

United States Patent McCabe 1 1451 Sept. 19,1972

1541 APPARATUS FOR APPLYING v ADHESIVE TO THE EDGES OF A SLIT TUBE [72] Inventor: Howard R. McCabe, Lancaster, Pa.

[73] Assignee: Armstrong Cork Company, Lancaster, Pa.-

[22] Filed: May 13, 1971 [21] Appl.No.: 143,140

52 us. c1. ..'....ll8/35, 118/38, 118/44, 118/239, 118/248 51 1m. 01. most 1/08, B05c 11/12 [58] Field of Search ..118/44, 642, 37, 68, 38, 239, 118/39, 248, 35; 117/43, 44, 4; 156/259; 30/9l.l,9l.2,92

[56] I References Cited I UNITED STATES PATENTS 1,323,212 11/1919 Bulley ..1l7/4 UX 1,785,762 12/1930 Bundy..- ......ll8/44 2,522,121 9/1950 Keller ..ll7/43- 3,538,885 11/1970 Tamura ..'..ll8/4 4 Primary Examiner-John P. Mclntosh Attorney-Clifford B. Price [57] ABSTRACT Foamed tubular insulation is provided with a slit down its longitudinal length so that it may be slid over a pipe. The apparatus herein opens up the tubing so that an adhesive coater may apply an adhesive to both edges of the slit in the tubing. A flattening structure opens up the tube so that the two surfaces to be coated are in the 'same horizontal plane, and a roll coating structure then applies adhesive to the edges in the same plane. The adhesive is permitted to dry and is then later solvent actuated, when it is to be utilized to fasten the two edges together.

4 Claims, 3 Drawing Figures PATENTEU SEP 1 9 INVENTOR HOWARD R. MCCABE BY ATTORNEY APPARATUS FOR APPLYING ADHESIVE TO THE EDGES OF A SLIT TUBE CROSS-REFERENCE TO RELATED APPLICATION This application is an improvement over that set forth in copending application Ser. No. 143,119, filed May 13, 1971, entitled Method and Apparatus for Applying Adhesive to the Edges of a Slit Tube, filed in the name of John J. Doherty.

BACKGROUND OF THE INVENTION tube is carried onto the rest of the processing apparatus. A second wedge-shaped tool further opens up on the edges of the slit, and the two edges forced together to bond them. Naturally, the glue that was utilized would be sticky and would ofttimes get on the hands of the individuals who were installing tubing. They would then have the problem of handling additional lengths of tubing with sticky hands. It therefore developed that it would be convenient to have a precoated adhesive on the edge of the tubing so that the installer of the tubing need only push the two edges together to fasten them together. However, normal pressure-sensitive adhesives could not be readily used because the tubing is packed in boxes, and there would be a tendency for the edges to inadvertently adhere together prior to the time they were installed on the pipe. Therefore a solvent-actuated adhesive was utilized, and all the installer needed to do now is apply a solvent to the edges of the tubing to actuate the adhesive and then push the edges together. The solvent itself would not be sticky, and the adhesive would not ooze out around the seam in the tubing and get on the hands of the installer. Consequently, the tubing is easier to handle and is installed in a much faster manner.

The idea of coating material with adhesive is relatively old. Also, the use of solvent-actuated adhesives is old; however, to date no one has developed a technique for applying adhesive to the edges of a slit tubing. The invention herein is a very specific solution to a very specific problem.

The invention herein is a modified structure over that of the above-mentioned copending application.

SUMMARY OF THE INVENTION The invention relates to an improved means for applying adhesive to the edges of a longitudinal slit in a hollow, expanded, foamed tubing of the type used for insulating pipes. In particular, the apparatus consists of a conveyer belt, a slitter, a tube opening apparatus and an adhesive coater. The conveyer carries the tube to the slitter. The slitter places the longitudinal cut in one wall of the tube. Directly behind the slitter, there is a wedge-shaped tool which enters the slit in the tubing and opens up the slit. A roller structure then enters the slit and holds the tube against the conveyer so that the the slit in the tube. Finally, a roller assembly forces the tube into its final U-shaped or semi-circular configuration, wherein the edges tobe coated with adhesive lie in a common horizontal plane at the top of the U. A rollcoating structure then applies an adhesive to these edges. The tube is then passed onto a heater structure which rapidly dries the adhesive. The tube is then permitted to return to its general round configuration. The adhesive is reactuated by an appropriate solvent on the job site, and the slit can thus be joined together by use of finger pressure, forcing the two adhesive-coated edges together.

BRIEF DESCRIPTION OF THE DRAWING FIG. I of the drawing is an isometric cross-sectional view of the tubing to be coated;

FIG. II is a top view of the coating apparatus; and

FIG. HI is a side view of the coating apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENT the longitudinal slit 4 therein. The longitudinal slit isv used to permit the tubing to be slid over a pipe. If the adhesive would be applied to the edges 6 of the longitudinal slit, these edges could be pushed together, and the adhesive would hold the edges together. Normally, the pipe covering in its unrelaxed state would have the two edges much closer together than is shown in the FIG. I representation. Therefore, if a pressure-sensitive adhesive had been used, there would be a good chance that these two edges would bond together when the tube is placed in a packing box. Consequently, a conventional solvent-actuated adhesive is utilized to coat the edges 6 so that they can be bonded together.

FIGS. II and III show the equipment which is utilized to spread apart the edges of the tube so that adhesive may be applied to the surfaces 6. The conveyer belt 8 passes around appropriate roll structures and moves the tube 2 in the direction of the arrow 10. The tube 2 is passed under a disc knife slitter assembly 12 which places the longitudinal slit in the upper wall of the tubing. Directly following the slitter 12, there is a wedgeshaped plow 14 whose narrow leading edge 16 is about the thickness of the slitter and slides into the slit cut in the tubing. The far end 18 of the plow is substantially thicker than the leading edge of the plow.

Directly following the plow 14, there is a thin roller structure 20 which is spaced from the conveyer slightly less than the thickness of the tube wall. This roller presses the tube against the conveyer so that there is frictional contact between the conveyer and the tube to force it on down through the rest of the processing apparatus. Following the roller 20, there is a second plow 22 which increases in thickness in the direction away from the roller 20. The increased thickness of the plow causes the slit in the tubing to be opened up so that the tube begins to approach its ultimate U-shaped configuration.

Near the end of the plow 22, there is positioned an inclined roller structure 24 which has a series of rollers 26. These rollers are freely rotating and simply roll across the tubing. As the tubing enters the rollers, it has begun to assume its U-shaped configuration. The rollers merely function to continue to push the tube towards its ultimate U-shape. The inclined relationship of the rollers helps to push the tube to its ultimate U- shape so that the edges of the slit are in the same parallel plane by the time the tubing approaches the coater assembly.

The coater assembly 28 consists basically of the roll coater 30, which places the adhesive on the two surfaces 6 of the tubing which are now held in the common plane, and the tubing itself is formed in the shape of a U.

As the tubing comes out from the roll coater, heater assemblies 32 dry the adhesive on the surfaces 6 before the tube returns to its closed state. The heater helps a tube, comprising a conveyer system for moving the tube, a slitter for placing a longitudinal slit in the tube on the surface of the tube away from the conveyer, a wedge-shaped bar for engaging the slit in the tube and spreading open the slit, a means for holding the tube in a generally U-shaped configuration on the conveyer, and a roll coat applicator for providing adhesive to the slit in the tubing as the tubing is fed under the applicator.

2. The apparatus of claim 1 wherein the wedgeshaped element for spreading the tube apart is actually two separate wedge-shaped elements with a roller therebetween, said roller functioning to maintain positive engagement between the conveyer and the tube so that the tube is conveyed along the conveyer.

3. The apparatus of claim 2 wherein the means for holding the tube in its general U-shaped configuration is a plurality of inclined roller structures which function to move the tube to its final U-shaped" conspeed the drying operation so that there is no danger figuration and hold the tube in that configuration until of the surfaces 6 sticking together when the tube is permitted to return to its normal relaxed state, which will have the two surfaces 6 closely adjacent to each other andthe tube in its general circular configuration.

What is claimed is:

1. An apparatus for applying adhesive to the edges of it passes to the coater assembly.

4. The apparatus of claim 3 wherein there is provided a heater structure for the rapid drying of the adhesive provided on the edges of the slit of the tubing by the coater assembly. 

2. The apparatus of claim 1 wherein the wedge-shaped element for spreading the tube apart is actually two separate wedge-shaped elements with a roller therebetween, said roller functioning to maintain positive engagement between the conveyer and the tube so that the tube is conveyed along the conveyer.
 3. The apparatus of claim 2 wherein the means for holding the tube in its general ''''U-shaped'''' configuration is a plurality of inclined roller structures which function to move the tube to its final ''''U-shaped'''' configuration and hold the tube in that configuration until it passes to the coater assembly.
 4. The apparatus of claim 3 wherein there is provided a heater structure for the rapid drying of the adhesive provided on the edges of the slit of the tubing by the coater assembly. 